1. Technical Field
The present invention relates generally to an electromagnetic wave shielding dielectric film, and more particularly to an electromagnetic wave shielding dielectric film that can improve the efficiency of electromagnetic wave shielding and enables the change or adjustment of a target frequency.
2. Description of the Related Art
Recently, with the dramatic development of digital technology, a semiconductor industry and the like, small-sized, lightweight, high-speed, and broad bandwidth electronic/electric devices have appeared. However, such electronic/electric devices are sensitive to slight electromagnetic wave interference, and thus easily suffer from erroneous operation. Countermeasures against electromagnetic wave interference include an electromagnetic wave blocking technique that is designed to block an electromagnetic wave through the reflection of the electromagnetic wave using metal, and an electromagnetic wave absorption technique that is designed to absorb an electromagnetic wave using an electromagnetic wave absorber. However, since the electromagnetic wave blocking technique is disadvantageous in that a blocked unnecessary electromagnetic wave causes additional damage, the electromagnetic wave absorption technique is now more frequently utilized.
FIG. 1 is a sectional view of a conventional monolayer electromagnetic wave absorber. Referring to FIG. 1, a conventional monolayer electromagnetic wave absorber 100 is described as follows. The monolayer electromagnetic wave absorber 100 includes an absorption layer 120, and a boundary layer 130 stacked on the rear surface of the absorption layer 120. The absorption layer 120 functions to absorb an electromagnetic wave, and includes a dielectric lossy material or a magnetic lossy material. The boundary layer 130 functions to block and reflect an electromagnetic wave that is not absorbed by but is transmitted through the absorption layer. The boundary layer 130 is formed of a perfect electric conductor.
As described above, an electromagnetic wave shielding structure using a common dielectric typically requires that a periodic arrangement of electric conductor patterns and a conductor layer for grounding should be provided on a dielectric substrate. Alternatively, an electromagnetic wave shielding structure using a common dielectric has a structure in which a dielectric lossy plate and a magnetic lossy plate are stacked in the form of multiple layers. This electromagnetic wave shielding structure exhibits absorption performance that is continuously attenuated while an electromagnetic wave incident onto the structure is passing through stacked absorption layers ranging from a surface layer to the lowermost layer. Furthermore, the stacked electromagnetic wave shielding structure includes a conductor or a conductive material. Therefore, the stacked electromagnetic wave shielding structure has the problems of having poor absorption or shielding efficiency, being sensitive to a change in target frequency and also having poor electrical stability.